Introduction
Polychlorinated biphenyls (PCBs) are chemical compounds with high cariogenic potential. They are a group of manufactured organic chemicals containing 209 individual chlorinated chemicals. PCBs were domestically manufactured from 1929; it was banned in 1979. They are used for the manufacturing of hydraulic equipment, electric and heat transfer equipment, and plasticizers in paints, plastics, rubber products, dyes, pigments, carbonless copy paper, and other industrial applications. They have a wide range of toxicity and are associated with harmful side effects on the immune, reproductive, and nervous systems.
What Are PCBs?
Polychlorinated biphenyls (PCBs) are chemicals used to manufacture industrial and consumer products. They are clear to yellow in color, solids, or oily liquids, with no smell or taste. Polychlorinated biphenyls (PCBs) are resistant to extreme temperature and pressure.
What Are the Uses of PCBs?
Used in the manufacture of products including:
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Transformers.
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Capacitors.
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Voltage regulators.
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Switches.
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Electromagnets and bushes.
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Oil in motors and hydraulic systems.
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Oil-based paints.
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Floor finish.
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Adhesives and tapes.
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Cable insulation.
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Fluorescent light ballasts.
How Are Humans Exposed to PCBs?
Polychlorinated biphenyls (PCBs) can be released into the environment through leaks from electric and other equipment, burning of waste containing PCBs, illegal and improper disposal and storage, and poorly maintained waste sites. Once these chemicals are released into the environment, they can continue cycling between air, water, and soil for a long period.
Polychlorinated biphenyls (PCBs) can be carried long distances and can be present in areas far from the main source, and are released into areas such as seawater and snow. Fish caught in contaminated water are the major dietary source of PCBs and cause potential health risks to people who eat them. Polychlorinated biphenyls (PCBs) can accumulate in the leaves and parts of food crops and plants.
What Happens When Humans Are Exposed to PCBs?
Polychlorinated biphenyls (PCBs) enter human cells and tissues through contaminated air, food, and the skin. When a person takes contaminated food, PCBs are readily absorbed from the digestive tract. Once it enters our body, polychlorinated biphenyls (PCBs) diffuse across the cell membrane and enter blood vessels and the lymphatic system. They contain a large number of chlorine atoms and are readily soluble in fats, and tend to accumulate in fat-rich tissues such as the brain, liver, and skin. Polychlorinated biphenyls (PCBs) can also pass into the placenta, umbilical cord blood, and breast milk from the mother's body and result in birth defects. PCBs can be transformed into persistent metabolites and accumulate in specific tissues and metabolites. After entering the tissues, they combine with glutathione and glucuronic acid (naturally present in the body), forming complex substances which are later excreted through urine and feces.
What Are the Health Problems Caused by PCBs?
Polychlorinated biphenyls (PCBs) cause a variety of adverse health effects. They have been shown to cause carcinogenic potential and affect the immune, nervous, reproductive, and endocrine systems.
1. Carcinogenic Potential - Polychlorinated biphenyls (PCBs) are considered potent carcinogens. Many studies conducted on humans and animals suggest an increased risk of cancer after PCB exposure. They increase the incidence of liver cancer, gallbladder cancer, biliary tract cancer, gastrointestinal tract cancer, brain cancer, and melanomas (skin cancer).
2. Developmental Defects - Women exposed to PCBs before or during pregnancy can give birth to children with lower intelligence quotient (IQ), neurological defects, and poor memory.
3. Hormone Imbalance - PCBs mimic the body’s natural hormones, like estrogen, and disrupt hormonal balance. The hormonal effects associated with PCBs are the following.
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Shortened menstrual cycle.
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Reduced sperm count.
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Altered sex organs
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Premature puberty.
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Altered estrogen and testosterone levels.
4. Immune Effects - Polychlorinated biphenyls (PCBs) exposure can seriously affect the immune system. The immune system is critical for fighting infections and protecting the body. The immune effects include the following.
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Decreased Resistance to Epstein-Barr Virus (EBV) Infections - Epstein-Barr Virus (EBV), also known as Human Herpesvirus 4. They cause infectious mononucleosis and spread through body fluids (primarily saliva).
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Decrease in the Size of the Thymus Gland - The thymus gland is a lymphatic organ that plays an important part in the immune system. It produces T-lymphocytes (T cells) which help the body fight infections.
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Reduced Immune Response - After exposure to polychlorinated biphenyls (PCBs), the ability of the body to produce antibodies against infection is reduced. It will lead to delayed immune response and susceptibility to infections.
5. Neurologic Effects - Polychlorinated biphenyls (PCBs) can lead to significant defects in neurological development, including visual recognition, learning, and short-term memory.
6. Thyroid Effects - PCBs also result in thyroid hormone imbalance, which results in defects in growth, behavioral development, and intellectual efficiency.
7. Acute Toxic Effects - Skin irritation, rashes, eye problems, and irritations of the nose and lungs can occur when a person is exposed to polychlorinated biphenyls (PCBs).
8. Other Effects - Liver toxicity, elevated blood pressure, serum triglyceride, and cholesterol levels.
How Can We Reduce the Risk of Exposure to PCBs?
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Wash fruits and vegetables before eating.
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Avoid contact with contaminated soil and sediments.
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Avoid consuming fish from contaminated water.
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Advise pregnant women, nursing mothers, women of childbearing age, and young children to avoid eating contaminated large fish with high-fat content.
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Old fluorescent light containing polychlorinated biphenyls (PCBs) should be replaced and discarded to avoid leakage and exposure.
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Children should be advised not to play with old electrical appliances, transformers, and chips that contain PCBs.
Conclusion
Polychlorinated biphenyls (PCBs) are chemicals that are released into the environment from industrial products. They are a mixture of more than 209 components and possess potential harmful health effects. After reaching the environment, it can remain for a long period and cause harmful effects. Exposure to. Polychlorinated biphenyls (PCBs) suppress the immune system and increase the risk of acquiring several diseases. They can also cause developmental defects, hormonal changes, and cause multi-system failures. Polychlorinated biphenyls (PCBs) have been banned since 1977 due to their potential health effects.